In certain vehicle seating applications, many seat functions require release of the vehicle seat back latch (recliner). One way this is accomplished is to provide a long release lever operationally connected to a variety of cables, with each cable associated with a particular seat function or method of release. As non-limiting examples, particular cables may be individually associated with a vehicle seat back manual release, power-actuated release, easy passenger entry function, and others.
During a dynamic event such as a collision, a combination of lever orientation with respect to a direction of impact and lever center of gravity can cause the seat back latch/recliner to actuate. That is, typically the center of mass 100 of a seat back recliner lever 102 is distanced from the lever pivot 104 (see FIG. 1A), and so on receipt of a suitable collision impact the lever tends to be displaced in a direction (arrow A) which may actuate the seat back latch/recliner. This inadvertent seat back actuation can create an unsafe situation.
Conventionally, this problem is addressed by including a return spring mechanism to overcome the inertial force of such dynamic events. With reference to FIG. 1B, a seat back recliner lever 102 is shown disposed on a portion of a seat back frame 106. The lever 102 is operationally associated with various cables 107 for actuating various seat functions as described above (seat back manual release, power-actuated release, easy passenger entry function, and others). In such prior art mechanisms, a return spring mechanism 108 is provided to overcome the tendency of the release lever 102 to displace on impact as described above. In this mechanism, a return spring 110 is disposed to counteract the effects of inertia on the release lever 102 encountered during certain impact events.
However, such return spring mechanisms 108 include attendant disadvantages. Because the spring 110 is continuously counteracting the motion of the release lever 102 during a seat back 112 releasing action, the effort required of a user or of an automated mechanism for releasing the seat back 112 is increased. Spring placement is an issue, as the spring 110 must be placed appropriately to provide the desired counteracting function without interfering with other seat mechanisms. Still more, multiple components are required to provide such a return spring mechanism 108, including the spring 110, a seat-mounted bracket 114 for engaging an end of the spring, a release lever tab 116 for engaging an opposed end of the spring, optionally a sleeve 118 for preventing damage to seat materials caused by the spring, and others. Such mechanisms are relatively complex and add to the cost and complexity of manufacture of the various involved components and so of the seat mechanism itself.
To solve the foregoing and other problems, the present disclosure provides a counterweighted seat back release mechanism. Advantageously, the described counterweight replaces the conventional return spring mechanism described above, providing the desired inertia-countering function with a less complex and so more robust and less costly mechanism.